Alicia Puccinelli of San Jose, left, and Ane Smith of Livermore, Calif show off their A's paraphernalia during Oakland Athletics Fan Fest at Jack London Square on Saturday, Jan. 27, 2018 in Oakland, Calif.

Alicia Puccinelli of San Jose, left, and Ane Smith of Livermore, Calif show off their A's paraphernalia during Oakland Athletics Fan Fest at Jack London Square on Saturday, Jan. 27, 2018 in Oakland, Calif.

Team president Dave Kaval said Saturday at the team’s FanFest in Jack London Square that the April 17 crowd “could be the largest attended game for baseball in the history of the Coliseum.”

The largest A’s game attendance in Coliseum history was 55,989 on June 26, 2004, against the Giants, but there is now more standing-room-only space.

Even with the Mount Davis tarps in place, the Coliseum’s capacity will increase this year to 48,592, a source said, thanks to some reconfigured seating, including the new “dugout seats” and updated field boxes. Foul territory will be unaffected by the new seating.

Another change at the Coliseum, The Chronicle has learned: Extended netting to protect fans in the lower level from foul balls and broken bats. After a toddler was injured by a foul ball at Yankee Stadium last year, many teams began to add more netting for seats near the field.

The A’s are likely to institute another monthly pass this season after success with a $19.99 monthly pass last summer; no details were available, but the team announced last year’s pass in May and it took effect in June.

The April 17 game falls on the 50th anniversary of the team’s first game in Oakland. Kaval promised “a massive birthday cake — hopefully enough for everyone there.”

FanFest was a big draw; the team estimated attendance at 25,000, easily topping the 15,000 that went last year, in the first year it was held at Jack London Square.

Briefly: Vice president of baseball operations Billy Beane said that left-hander A.J. Puk, the team’s top pick in 2016, could be an option this season, as could infielder Jorge Mateo, who was obtained in the Sonny Gray deal last summer. In the event of a need, each is “a phone call away,” Beane said. … Beane said that right-hander James Kaprielian, also acquired in the Gray deal and coming back from surgery, will throw off the mound by May. … Third baseman Matt Chapman, who lived with Kaprielian in Southern California this offseason, said, “He looks really good. I watched him throw and everything looks good. He’s a hard worker, and it doesn’t surprise me he’s bouncing back quick.” … Chapman says he’s gained 10 pounds this winter, putting him at 220. … Chad Pinder said he didn’t fully recover from last year’s concussion until a month into the offseason. … Pinder has added more running to his offseason workouts, a nod to moving from the infield to the outfield. He wants to make sure he has no repeats of last year’s hamstring strain, and he believes he’s also picked up a little speed.